In recent years, to increase semiconductor integration, many proposed configurations of semiconductor storage devices have memory cells that are arranged three-dimensionally. In this kind of three-dimensionally structured semiconductor storage device, a capacitive component is needed, much like the case of conventional plane-structured semiconductor storage devices. The capacitive component is used for boosting the power supply voltage or as a supplementary component. Similar to a memory cell, reduction of the occupied area by a capacitive component is recognized to be beneficial.